Calculating device.



No. 683,8!4. Patented Oct. l 190i.

I E. W. THOMAS.

CALCULATING DEVICE.

(Application filed Jun. 4. 1901.)

(No llodal.)

IE; E.

WITNESSES INJKQNTOR W W ZIK/J 4 km ORNEYS 1m: norms vcnn co. Womumo, msummou. by c UNITED STATES PATENT OFFICE.

EDIVARD WILLIAM THOMAS, OF SYDNEY, NEIV SOUTH ALES.

CALCULATING DEVICE.

SPECIFICATION formingpart of Letters Patent No. 683,814, dated October 1, 1901.

Application filed January 4,1901. Serial No. 42,086. (lie model.)

To all 'whmn it may concern:

Be it known that I, EDWARD WILLIAM THOMAS, a subject of the Queen of Great Britain, residing at \Voollahra, Sydney, New South Wales, have invented certain new and useful Improvements in Discount and Interest Calculating Devices, of which the following is a full and complete specification, such as will enable those skilled in the art to which it appertains to make and use the same.

This invention relates to discount and interest calculating devices; and the object thereof is to provide a device of this class whereby varied percentages of a plurality of principals or sums of money may be mechanically calculated.

The invention consists in the novelconstruction and relative arrangement of parts hereinafter set forth.

In the accompanying drawings, forming part of this specification, in which like reference characters denote like parts in both views, Figure 1 is a plan view of a calculating device constructed according to my invention, and Fig. 2 is a transverse diametrical section thereof on the line 2 2 thereof.

In the practice of my invention I provide two relatively movable members 3 and 4:, the member 3 being designed to bear, as hereinafter described, the numerical symbols of the several principals or sums of money, as well as the several discount or interest percentages thereof, which are denoted in the operation of the device by the member 4, which is manipulated as hereinafter described. The member 3 consists, preferably, of a circular disk of wood, cardboard, metal, or other suitable substance, upon the upper surface of which are arranged a plurality of concentric circles 5, the diameters of which increase relatively from the innermost to the outermost by a constant relation, with the exception of the innermost circle and that next adjacent thereto, respectively 5 and 5 which are separated by an annular space 5, which is of greater transverse dimension than any of the annular spaces between the remainder of the circles 5. IVithin the annular spaces 5 are arranged a plurality of radial lines 5 and alternating with the several radial lines in the spaces 5 therebetween are arranged the symbolic representations of the several principals or sums upon which the calculations incident to the operation of my invention are based. In the present instance these symbolic representations consist of figures ranging throughout the extent of the annular space 5 from 33 upwardly according to the English system of currency, the highest denomination represented being 35. It is manifest, however, that any system of currency or any numerical scheme may be employed in substitution for that shown and that the interest and discount values hereinafter described may be accordingly substituted for. The member 4: consists of a sheet or strip of suitable rigid material, preferably cardboard, wood, or metal, which is centrally pivoted at 6 above the member 3, the major portion of the edge portion of which, 6, is segmental in contour and the remainder of the edge portion of which embraces a projecting wing 6 embodying a plurality of peripheral points or pointers 7, 8, 9, 10, 11, 12, 13, ll, 15, and 16, the outer extremities of which terminate within a spiral curve, as clearly shown in Fig. 1. The edge portion 6 embodies a projecting pointer 7. The pointer 7 terminates at itsouter edge in registration with the innermost circle 5 and is read in connection with the spaces 5, which alternate with the radial lines 5. Arranged upon the upper surface of each of the points or pointers 7 to 16, inclusively, are the interest-symb 1 p ti ly, u cc 7%, cc ,7: 5,7: ,77 3%, 211;, l-lr, and 1; but it is manifest that these symbols may be varied in their application to the member 4, as desired, according to the requirements of the system of calculation in use. The interest results or totals symbols are arranged in the annular spaces alternating with the several concentric circles 5, and the scheme of arrangement thereof relative to the principal-symbol arranged within the spaces 5 is determined with relation to the position of the several pointers 7 to 16, inclusively, to the pointer 7, the position of any one of the interesttotal symbols upon the upper surface of the member 3 being determined at a given principal by moving the pointer 7 into registration with the space 5*, in which the principal-symbol lies, and arranging the resultant interest total symbol upon the member 3 in registration with that pointer 7 to 16, inclusively, which bears the interest-symbol in question.

It will be seen that due to the formation of the portion 6 of the member 4 and the spiral form of a curved line drawn to touch the outermost point of each of the pointers 7 to 16, inclusively,each of said last-mentioned pointers at all times registers with one of the concentric circles 5. Hence the interest-total symbols at a given rate of interest and for any one of the principals will always be found in thespace exterior of the circle 5, in registration with which circle the respective pointers '7 to 16,inclusively, travel in the rotation of the member 4.

To illustrate the operation of the calculating device above described, let it be assumed that it is required to calculate the interest or discount of one pound sterling at three and one-half per cent. for one year. The memberet is rotated to bring the pointer 7 into registration with that space 5 in which appears the principal-symbol l:0:0, the drawings illustrating the member 4 and pointer 7 in such position. The several pointers 7 to 16, inclusively, are now examined until that one thereof, 12, which bears the interest-symbol 3% is found, and in registration therewith exterior of that circle 5 in connection with which the pointer 12 is read is found the interest-total symbol 010 :8%. A continued and varied manipulation of the member 4 in performing a series of calculations allied to that last described will disclose-the fact that a complete traverse of any one of the pointers 7 to 16, inclusively, in its respective circular path above the member 3 will successively bring the said pointer into the several positions necessary to cause the same to register with the several interest-totals bearing the same relations to the respective interest-symbol as the latter bears to the several principal-symbols successively pointed out by the pointer 7 which manifestly travels circularly in registration with the circle 5 in step with all of the pointers 7 to 16, inclusively.

In the drawings I have only shown a sufficient number of interest-total symbols to illustrate the principle of my invention, it being manifest that the number and character of such symbols may be varied through a wide range within the spirit of my invention, as well as may the principal-symbols and the interest or discount symbols. It is further manifest that the calculating device above described may be applied to the performance of many and varied calculations in mathematics without departing from the spirit of my invention. I therefore do not limit myself to the specific form and arrangement of parts hereinabove described nor to the specific details disclosed as incident to the manipulation of the device, reserving the right to vary the same within the scope of my in vention and of the claims hereto appended.

Having fully described my invention, I claim as new and desire to secure by Letters Patent- 1. Theherein-describedcalculatingdevice, comprising a main member provided upon its upper surface with a plurality of concentric circles, the innermost two of which are connected by a plurality of spaced radial lines, principal-symbols arranged alternating with said radial lines and between the said innermost circles; said main member being further provided with a plurality of interesttotal symbols which are arranged in predetermined positions in the circular spaces which alternate with the several concentric circles; and a supplemental member pivoted above said main member concentrically with the circles arranged thereon and embodying an edge portion 6 provided with a pointer 7, and an edge portion 6 provided with the pointers 7, 8, 9, 10, 11, 12, 13, 14, 15 and 16, each of said pointers terminating in registration with one of said concentric circles, substantially as shown and described.

2. A calculating device of the class described, comprising two relatively revoluble members, the first of which is provided upon its surface with a circular series of principalsymbols and a plurality of circular series of interest-total symbols arranged spirally with reference to said series of principal-symbols, the second member consisting of a central segmental portion, provided at one side with a wing or projection, one side of which is spirally formed and the other straight or radial, said second member being pivotally connected with said first member concentricallyof and within said circular series of principalsymbols arranged upon said first member, and being provided with a main pointer which reads in connection with said series of principal-symbols, and the wing or projection forming a part of the second member being also provided at the spiral edge thereof with a plurality of supplemental pointers each of which terminates at a point of varying radial distance from the pivotal point of said member and is read in connection with one of said circular series of interest-total symbols, each' of said supplemental pointers being also provided with an interest-symbol, substantially as shown and described.

In testimony that I claim the foregoing as my invention I have signed my name, in presence of the subscribing witnesses, this 27th day of November, 1900.

EDWARD WILLIAM THOMAS.

Witnesses:

Jimms Tummy, 1 ALBERT EDWARD CRAWFORD Jonrsror.

ICC 

